lst = ['金星', '木星', '水星', '土星', '火星', '金星', '木星', '水星', '土星', '火星']

new_lst = []

# (1) 遍历 + not in
for item in lst:
    if item not in new_lst:
        new_lst.append(item)  # 将item添加到新列表中
print(new_lst)

# (2) 遍历 + not in
new_lst2 = []
for i in range(len(lst)):
    if lst[i] not in new_lst2:
        new_lst2.append(lst[i])
print(new_lst2)

# (3) 使用集合去重
s_lst = set(lst)
new_lst3 = list(s_lst)
new_lst3.sort(key=lst.index)
print(new_lst3)